1. Field
Embodiments described herein relate to a non-volatile semiconductor memory device.
2. Description of the Related Art
As a memory storing large volumes of data for use, a resistance variable memory (ReRAM: Resistive RAM), which can be three-dimensionally formed easily, draws attention. Such a resistance variable memory is characterized by asymmetry properties in which voltage-current characteristics vary significantly depending on a direction of voltage to be applied to a memory cell.
On the other hand, the cell must have favorable data retention characteristics in order to make a non-volatile memory, but since the data retention characteristics depend on a physical state of a substance forming resistance, sufficient state retention cannot be achieved in many cases.